#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2011 thomasv@gitorious
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.


import sys, base64, os, re, hashlib, socket, getpass, copy, operator, ast
from decimal import Decimal
from ecdsa.util import string_to_number

try:
    import ecdsa  
except:
    print "python-ecdsa does not seem to be installed. Try 'sudo easy_install ecdsa'"
    sys.exit(1)

try:
    import aes
except:
    print "AES does not seem to be installed. Try 'sudo easy_install slowaes'"
    sys.exit(1)


############ functions from pywallet ##################### 

addrtype = 0

def hash_160(public_key):
    md = hashlib.new('ripemd160')
    md.update(hashlib.sha256(public_key).digest())
    return md.digest()

def public_key_to_bc_address(public_key):
    h160 = hash_160(public_key)
    return hash_160_to_bc_address(h160)

def hash_160_to_bc_address(h160):
    vh160 = chr(addrtype) + h160
    h = Hash(vh160)
    addr = vh160 + h[0:4]
    return b58encode(addr)

def bc_address_to_hash_160(addr):
    bytes = b58decode(addr, 25)
    return bytes[1:21]

__b58chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
__b58base = len(__b58chars)

def b58encode(v):
    """ encode v, which is a string of bytes, to base58.		
    """

    long_value = 0L
    for (i, c) in enumerate(v[::-1]):
        long_value += (256**i) * ord(c)

    result = ''
    while long_value >= __b58base:
        div, mod = divmod(long_value, __b58base)
        result = __b58chars[mod] + result
        long_value = div
    result = __b58chars[long_value] + result

    # Bitcoin does a little leading-zero-compression:
    # leading 0-bytes in the input become leading-1s
    nPad = 0
    for c in v:
        if c == '\0': nPad += 1
        else: break

    return (__b58chars[0]*nPad) + result

def b58decode(v, length):
    """ decode v into a string of len bytes
    """
    long_value = 0L
    for (i, c) in enumerate(v[::-1]):
        long_value += __b58chars.find(c) * (__b58base**i)

    result = ''
    while long_value >= 256:
        div, mod = divmod(long_value, 256)
        result = chr(mod) + result
        long_value = div
    result = chr(long_value) + result

    nPad = 0
    for c in v:
        if c == __b58chars[0]: nPad += 1
        else: break

    result = chr(0)*nPad + result
    if length is not None and len(result) != length:
        return None

    return result


def Hash(data):
    return hashlib.sha256(hashlib.sha256(data).digest()).digest()

def EncodeBase58Check(vchIn):
    hash = Hash(vchIn)
    return b58encode(vchIn + hash[0:4])

def DecodeBase58Check(psz):
    vchRet = b58decode(psz, None)
    key = vchRet[0:-4]
    csum = vchRet[-4:]
    hash = Hash(key)
    cs32 = hash[0:4]
    if cs32 != csum:
        return None
    else:
        return key

def PrivKeyToSecret(privkey):
    return privkey[9:9+32]

def SecretToASecret(secret):
    vchIn = chr(addrtype+128) + secret
    return EncodeBase58Check(vchIn)

def ASecretToSecret(key):
    vch = DecodeBase58Check(key)
    if vch and vch[0] == chr(addrtype+128):
        return vch[1:]
    else:
        return False

########### end pywallet functions #######################


def int_to_hex(i, length=1):
    s = hex(i)[2:].rstrip('L')
    s = "0"*(2*length - len(s)) + s
    return s.decode('hex')[::-1].encode('hex')



EncodeAES = lambda secret, s: base64.b64encode(aes.encryptData(secret,s))
DecodeAES = lambda secret, e: aes.decryptData(secret, base64.b64decode(e))



# secp256k1, http://www.oid-info.com/get/1.3.132.0.10
_p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2FL
_r = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141L
_b = 0x0000000000000000000000000000000000000000000000000000000000000007L
_a = 0x0000000000000000000000000000000000000000000000000000000000000000L
_Gx = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798L
_Gy = 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8L
curve_secp256k1 = ecdsa.ellipticcurve.CurveFp( _p, _a, _b )
generator_secp256k1 = ecdsa.ellipticcurve.Point( curve_secp256k1, _Gx, _Gy, _r )
oid_secp256k1 = (1,3,132,0,10)
SECP256k1 = ecdsa.curves.Curve("SECP256k1", curve_secp256k1, generator_secp256k1, oid_secp256k1 ) 


def filter(s): 
    out = re.sub('( [^\n]*|)\n','',s)
    out = out.replace(' ','')
    out = out.replace('\n','')
    return out

def raw_tx( inputs, outputs, for_sig = None ):
    s  = int_to_hex(1,4)                                     +   '     version\n' 
    s += int_to_hex( len(inputs) )                           +   '     number of inputs\n'
    for i in range(len(inputs)):
        _, _, p_hash, p_index, p_script, pubkey, sig = inputs[i]
        s += p_hash.decode('hex')[::-1].encode('hex')        +  '     prev hash\n'
        s += int_to_hex(p_index,4)                           +  '     prev index\n'
        if for_sig is None:
            sig = sig + chr(1)                               # hashtype
            script  = int_to_hex( len(sig))                  +  '     push %d bytes\n'%len(sig)
            script += sig.encode('hex')                      +  '     sig\n'
            pubkey = chr(4) + pubkey
            script += int_to_hex( len(pubkey))               +  '     push %d bytes\n'%len(pubkey)
            script += pubkey.encode('hex')                   +  '     pubkey\n'
        elif for_sig==i:
            script = p_script                                +  '     scriptsig \n'
        else:
            script=''
        s += int_to_hex( len(filter(script))/2 )             +  '     script length \n'
        s += script
        s += "ffffffff"                                      +  '     sequence\n'
    s += int_to_hex( len(outputs) )                          +  '     number of outputs\n'
    for output in outputs:
        addr, amount = output
        s += int_to_hex( amount, 8)                          +  '     amount: %d\n'%amount 
        script = '76a9'                                      # op_dup, op_hash_160
        script += '14'                                       # push 0x14 bytes
        script += bc_address_to_hash_160(addr).encode('hex')
        script += '88ac'                                     # op_equalverify, op_checksig
        s += int_to_hex( len(filter(script))/2 )             +  '     script length \n'
        s += script                                          +  '     script \n'
    s += int_to_hex(0,4)                                     # lock time
    if for_sig is not None: s += int_to_hex(1, 4)            # hash type
    return s

class InvalidPassword(Exception):
    pass



from version import ELECTRUM_VERSION, SEED_VERSION


class Wallet:
    def __init__(self, wallet_path):

        self.electrum_version = ELECTRUM_VERSION
        self.seed_version = SEED_VERSION

        self.gap_limit = 5           # configuration
        self.host = 'ecdsa.org'
        self.port = 50000
        self.fee = 50000
        self.servers = ['ecdsa.org','electrum.novit.ro']  # list of default servers
        self.master_public_key = None

        # saved fields
        self.use_encryption = False
        self.addresses = []          # receiving addresses visible for user
        self.change_addresses = []   # addresses used as change
        self.seed = ''               # encrypted
        self.status = {}             # current status of addresses
        self.history = {}
        self.labels = {}             # labels for addresses and transactions
        self.addressbook = []        # outgoing addresses, for payments
        self.blocks = 0 

        # not saved
        self.message = ''
        self.tx_history = {}
        self.rtime = 0

        self.init_path(wallet_path)


    def init_path(self, wallet_path):

        if wallet_path is not None:
            self.path = wallet_path
        else:
            # backward compatibility: look for wallet file in the default data directory
            if "HOME" in os.environ:
                wallet_dir = os.path.join( os.environ["HOME"], '.electrum')
            elif "LOCALAPPDATA" in os.environ:
                wallet_dir = os.path.join( os.environ["LOCALAPPDATA"], 'Electrum' )
            elif "APPDATA" in os.environ:
                wallet_dir = os.path.join( os.environ["APPDATA"], 'Electrum' )
            else:
                raise BaseException("No home directory found in environment variables.")

            if not os.path.exists( wallet_dir ): os.mkdir( wallet_dir )
            self.path = os.path.join( wallet_dir, 'electrum.dat' )

    def new_seed(self, password):
        seed = "%032x"%ecdsa.util.randrange( pow(2,128) )
        self.init_mpk(seed)
        # encrypt
        self.seed = wallet.pw_encode( seed, password )

    def init_mpk(self,seed):
        # public key
        curve = SECP256k1
        secexp = self.stretch_key(seed)
        master_private_key = ecdsa.SigningKey.from_secret_exponent( secexp, curve = SECP256k1 )
        self.master_public_key = master_private_key.get_verifying_key().to_string()

    def is_mine(self, address):
        return address in self.addresses or address in self.change_addresses

    def is_change(self, address):
        return address in self.change_addresses

    def is_valid(self,addr):
        ADDRESS_RE = re.compile('[1-9A-HJ-NP-Za-km-z]{26,}\\Z')
        if not ADDRESS_RE.match(addr): return False
        h = bc_address_to_hash_160(addr)
        return addr == hash_160_to_bc_address(h)

    def stretch_key(self,seed):
        oldseed = seed
        for i in range(100000):
            seed = hashlib.sha256(seed + oldseed).digest()
        return string_to_number( seed )

    def get_sequence(self,n,for_change):
        return string_to_number( Hash( "%d:%d:"%(n,for_change) + self.master_public_key ) )

    def get_private_key2(self, address, password):
        """  Privatekey(type,n) = Master_private_key + H(n|S|type)  """
        if address in self.addresses:
            n = self.addresses.index(address)
            for_change = False
        elif address in self.change_addresses:
            n = self.change_addresses.index(address)
            for_change = True
        else:
            raise BaseException("unknown address")

        seed = self.pw_decode( self.seed, password)
        secexp = self.stretch_key(seed)
        order = generator_secp256k1.order()
        privkey_number = ( secexp + self.get_sequence(n,for_change) ) % order
        private_key = ecdsa.SigningKey.from_secret_exponent( privkey_number, curve = SECP256k1 )
        # sanity check
        #public_key = private_key.get_verifying_key()
        #assert address == public_key_to_bc_address( '04'.decode('hex') + public_key.to_string() )
        return private_key


    def create_new_address2(self, for_change):
        """   Publickey(type,n) = Master_public_key + H(n|S|type)*point  """
        curve = SECP256k1
        n = len(self.change_addresses) if for_change else len(self.addresses)
        z = self.get_sequence(n,for_change)
        master_public_key = ecdsa.VerifyingKey.from_string( self.master_public_key, curve = SECP256k1 )
        pubkey_point = master_public_key.pubkey.point + z*curve.generator
        public_key2 = ecdsa.VerifyingKey.from_public_point( pubkey_point, curve = SECP256k1 )
        address = public_key_to_bc_address( '04'.decode('hex') + public_key2.to_string() )
        if for_change:
            self.change_addresses.append(address)
        else:
            self.addresses.append(address)
        self.save()
        return address
        
    def recover(self):
        # todo: recover receiving addresses from tx
        is_found = False
        while True:
            addr = self.create_new_address2(True)
            self.history[addr] = h = self.retrieve_history(addr)
            self.status[addr] = h[-1]['blk_hash'] if h else None
            print "recovering", addr
            if self.status[addr] is not None: 
                is_found = True
            else:
                break

        num_gap = 0
        while True:
            addr = self.create_new_address2(False)
            self.history[addr] = h = self.retrieve_history(addr)
            self.status[addr] = h[-1]['blk_hash'] if h else None
            print "recovering", addr
            if self.status[addr] is None:
                num_gap += 1
                if num_gap == self.gap_limit: break
            else:
                is_found = True
                num_gap = 0

        if not is_found: return False

        # remove limit-1 addresses.
        n = self.gap_limit
        self.addresses = self.addresses[:-n]

        # history and addressbook
        self.update_tx_history()
        for tx in self.tx_history.values():
            if tx['value']<0:
                for i in tx['outputs']:
                    if not self.is_mine(i) and i not in self.addressbook:
                        self.addressbook.append(i)
        # redo labels
        self.update_tx_labels()
        return True

    def save(self):
        s = {
            'seed_version':self.seed_version,
            'use_encryption':self.use_encryption,
            'master_public_key': self.master_public_key,
            'fee':self.fee,
            'host':self.host,
            'port':self.port,
            'blocks':self.blocks,
            'seed':self.seed,
            'addresses':self.addresses,
            'change_addresses':self.change_addresses,
            'status':self.status,
            'history':self.history, 
            'labels':self.labels,
            'contacts':self.addressbook
            }
        f = open(self.path,"w")
        f.write( repr(s) )
        f.close()

    def read(self):
        try:
            f = open(self.path,"r")
            data = f.read()
            f.close()
        except:
            return False
        try:
            d = ast.literal_eval( data )
            self.seed_version = d.get('seed_version')
            self.master_public_key = d.get('master_public_key')
            self.use_encryption = d.get('use_encryption')
            self.fee = int( d.get('fee') )
            self.host = d.get('host')
            self.port = d.get('port')
            self.blocks = d.get('blocks')
            self.seed = d.get('seed')
            self.addresses = d.get('addresses')
            self.change_addresses = d.get('change_addresses')
            self.status = d.get('status')
            self.history = d.get('history')
            self.labels = d.get('labels')
            self.addressbook = d.get('contacts')
        except:
            raise BaseException("Error; could not parse wallet. If this is an old wallet format, please use upgrade.py.",0)
        if self.seed_version != SEED_VERSION:
            raise BaseException("""Seed version mismatch: your wallet seed is deprecated.
Please create a new wallet, and send your coins to the new wallet.
We apologize for the inconvenience. We try to keep this kind of upgrades as rare as possible.
See the release notes for more information.""",1)


        self.update_tx_history()
        return True
        
    def get_new_address(self):
        n = 0 
        for addr in self.addresses[-self.gap_limit:]:
            if not self.history.get(addr): 
                n = n + 1
        if n < self.gap_limit:
            new_address = self.create_new_address2(False)
            self.history[new_address] = [] #get from server
            return True, new_address
        else:
            return False, "The last %d addresses in your list have never been used. You should use them first, or increase the allowed gap size in your preferences. "%self.gap_limit

    def get_addr_balance(self, addr):
        h = self.history.get(addr)
        if not h: return 0,0
        c = u = 0
        for item in h:
            v = item['value']
            if item['height']:
                c += v
            else:
                u += v
        return c, u

    def get_balance(self):
        conf = unconf = 0
        for addr in self.addresses: 
            c, u = self.get_addr_balance(addr)
            conf += c
            unconf += u
        return conf, unconf

    def use_http(self): 
        return self.port in [80,8080,443]

    def request(self, request ):
        import time
        t1 = time.time()

        if self.use_http():
            import httplib, urllib
            params = urllib.urlencode({'q':request})
            headers = {"Content-type": "application/x-www-form-urlencoded", "Accept": "text/plain"}
            conn = httplib.HTTPSConnection(self.host) if self.port == 443 else httplib.HTTPConnection(self.host)
            conn.request("POST", "/electrum.php", params, headers)
            response = conn.getresponse()
            if response.status == 200:
                out = response.read()
            else: out = ''
            conn.close()
        else:
            request += "#"
            s = socket.socket( socket.AF_INET, socket.SOCK_STREAM)
            s.connect(( self.host, self.port))
            s.send( request )
            out = ''
            while 1:
                msg = s.recv(1024)
                if msg: out += msg
                else: break
            s.close()

        self.rtime = time.time() - t1
        return out

    def send_tx(self, data):
        return self.request( repr ( ('tx', data )))

    def retrieve_history(self, address):
        return ast.literal_eval( self.request( repr ( ('h', address ))) )

    def poll(self):
        return ast.literal_eval( self.request( repr ( ('poll', self.session_id ))))

    def new_session(self):
        self.session_id, self.message = ast.literal_eval( self.request( repr ( ('new_session', repr( (self.electrum_version, self.addresses)) ))))

    def update_session(self):
        return self.request( repr ( ('update_session', repr((self.session_id,self.addresses)))))

    def get_servers(self):
        self.servers = map( lambda x:x[1], ast.literal_eval( self.request( repr ( ('peers', '' )))) )
        
    def update(self):
        blocks, changed_addresses = self.poll()
        if blocks == -1: raise BaseException("session not found")
        self.blocks = int(blocks)
        for addr, blk_hash in changed_addresses.items():
            if self.status.get(addr) != blk_hash:
                print "updating history for", addr
                self.history[addr] = self.retrieve_history(addr)
                self.status[addr] = blk_hash
        self.update_tx_history()
        if changed_addresses:
            return True
        else:
            return False

    def choose_tx_inputs( self, amount, fixed_fee ):
        """ todo: minimize tx size """
        total = 0
        fee = self.fee if fixed_fee is None else fixed_fee
        inputs = []
        for addr in self.addresses:
            h = self.history.get(addr)
            for item in h:
                if item.get('raw_scriptPubKey'):
                    v = item.get('value')
                    total += v
                    inputs.append((addr, v, item['tx_hash'], item['pos'], item['raw_scriptPubKey'], None, None) )
                    fee = self.fee*len(inputs) if fixed_fee is None else fixed_fee
                    if total >= amount + fee: break
            if total >= amount + fee: break
        else:
            #print "not enough funds: %d %d"%(total, fee)
            inputs = []
        return inputs, total, fee

    def choose_tx_outputs( self, to_addr, amount, fee, total ):
        outputs = [ (to_addr, amount) ]
        change_amount = total - ( amount + fee )
        if change_amount != 0:
            # first look for unused change addresses 
            for addr in self.change_addresses:
                if self.history.get(addr): continue
                change_address = addr
                break
            else:
                change_address = self.create_new_address2(True)
                print "new change address", change_address
            outputs.append( (change_address,  change_amount) )
        return outputs

    def sign_inputs( self, inputs, outputs, password ):
        s_inputs = []
        for i in range(len(inputs)):
            addr, v, p_hash, p_pos, p_scriptPubKey, _, _ = inputs[i]
            private_key = self.get_private_key2(addr, password)
            public_key = private_key.get_verifying_key()
            pubkey = public_key.to_string()
            tx = filter( raw_tx( inputs, outputs, for_sig = i ) )
            sig = private_key.sign_digest( Hash( tx.decode('hex') ), sigencode = ecdsa.util.sigencode_der )
            assert public_key.verify_digest( sig, Hash( tx.decode('hex') ), sigdecode = ecdsa.util.sigdecode_der)
            s_inputs.append( (addr, v, p_hash, p_pos, p_scriptPubKey, pubkey, sig) )
        return s_inputs

    def pw_encode(self, s, password):
        if password:
            secret = Hash(password)
            return EncodeAES(secret, s)
        else:
            return s

    def pw_decode(self, s, password):
        if password:
            secret = Hash(password)
            d = DecodeAES(secret, s)
            try:
                d.decode('hex')
            except:
                raise InvalidPassword()
            return d
        else:
            return s

    def get_tx_history(self):
        lines = self.tx_history.values()
        lines = sorted(lines, key=operator.itemgetter("nTime"))
        return lines

    def update_tx_history(self):
        self.tx_history= {}
        for addr in self.addresses:
            h = self.history.get(addr)
            if h is None: continue
            for tx in h:
                tx_hash = tx['tx_hash']
                line = self.tx_history.get(tx_hash)
                if not line:
                    self.tx_history[tx_hash] = copy.copy(tx)
                    line = self.tx_history.get(tx_hash)
                else:
                    line['value'] += tx['value']
                if line['height'] == 0:
                    line['nTime'] = 1e12
        self.update_tx_labels()

    def update_tx_labels(self):
        for tx in self.tx_history.values():
            default_label = ''
            if tx['value']<0:
                for o_addr in tx['outputs']:
                    if not self.is_change(o_addr):
                        dest_label = self.labels.get(o_addr)
                        if dest_label:
                            default_label = 'to: ' + dest_label
                        else:
                            default_label = 'to: ' + o_addr
            else:
                for o_addr in tx['outputs']:
                    if self.is_mine(o_addr) and not self.is_change(o_addr):
                        dest_label = self.labels.get(o_addr)
                        if dest_label:
                            default_label = 'at: ' + dest_label
                        else:
                            default_label = 'at: ' + o_addr
            tx['default_label'] = default_label

    def mktx(self, to_address, amount, label, password, fee=None):
        if not self.is_valid(to_address):
            return False, "Invalid address"
        inputs, total, fee = wallet.choose_tx_inputs( amount, fee )
        if not inputs: return False, "Not enough funds %d %d"%(total, fee)
        try:
            outputs = wallet.choose_tx_outputs( to_address, amount, fee, total )
            s_inputs = wallet.sign_inputs( inputs, outputs, password )
        except InvalidPassword:
            return False, "Wrong password"
        tx = filter( raw_tx( s_inputs, outputs ) )
        if to_address not in self.addressbook:
            self.addressbook.append(to_address)
        if label: 
            tx_hash = Hash(tx.decode('hex') )[::-1].encode('hex')
            wallet.labels[tx_hash] = label
        wallet.save()
        return True, tx

    def sendtx(self, tx):
        tx_hash = Hash(tx.decode('hex') )[::-1].encode('hex')
        out = self.send_tx(tx)
        if out != tx_hash:
            return False, "error: " + out
        return True, out



from optparse import OptionParser

if __name__ == '__main__':
    known_commands = ['help', 'validateaddress', 'balance', 'contacts', 'create', 'payto', 'sendtx', 'password', 'newaddress', 'addresses', 'history', 'label', 'gui', 'mktx','seed','t2']

    usage = "usage: %prog [options] command args\nCommands: "+ (', '.join(known_commands))

    parser = OptionParser(usage=usage)
    parser.add_option("-w", "--wallet", dest="wallet_path", help="wallet path (default: electrum.dat)")
    parser.add_option("-a", "--all", action="store_true", dest="show_all", default=False, help="show all addresses")
    parser.add_option("-b", "--balance", action="store_true", dest="show_balance", default=False, help="show the balance at listed addresses")
    parser.add_option("-k", "--keys",action="store_true", dest="show_keys",default=False, help="show the private keys of listed addresses")
    parser.add_option("-f", "--fee", dest="tx_fee", default=0.005, help="set tx fee")
    options, args = parser.parse_args()
    try:
        cmd = args[0]
    except:
        cmd = "gui"
    try:
        firstarg = args[1]
    except:
        firstarg = ''

    if cmd not in known_commands:
        cmd = 'help'

    wallet = Wallet(options.wallet_path)

    if cmd == 'gui':
        import gui
        gui.init_wallet(wallet)
        gui = gui.BitcoinGUI(wallet)
        gui.main()
        wallet.save()
        sys.exit(0)

    if not wallet.read() and cmd not in ['help','create']:
        print "Wallet file not found."
        print "Type 'electrum.py create' to create a new wallet, or provide a path to a wallet with the -d option"
        sys.exit(0)
    
    if cmd == 'create':
        if wallet.read():
            print "remove the existing wallet first!"
            sys.exit(0)
        password = getpass.getpass("Password (hit return if you do not wish to encrypt your wallet):")
        if password:
            password2 = getpass.getpass("Confirm password:")
            if password != password2:
                print "error"
                sys.exit(1)
        else:
            password = None
            print "in order to use wallet encryption, please install pycrypto  (sudo easy_install pycrypto)"

        host = raw_input("server (default:ecdsa.org):")
        port = raw_input("port (default:50000):")
        fee = raw_input("fee (default 0.005):")
        if fee: wallet.fee = float(fee)
        if host: wallet.host = host
        if port: wallet.port = int(port)
        seed = raw_input("if you are restoring an existing wallet, enter the seed. otherwise just press enter: ")
        wallet.gap_limit = 5
        if seed:
            wallet.seed = seed
            gap = raw_input("gap limit (default 5):")
            if gap: wallet.gap_limit = int(gap)
            print "recovering wallet..."
            r = wallet.recover()
            if r:
                print "recovery successful"
                wallet.save()
            else:
                print "no wallet found"
        else:
            wallet.new_seed(None)
            print "Your seed is", wallet.seed
            print "Please store it safely"
            # generate first key
            wallet.create_new_address2(False)

    # check syntax
    if cmd in ['payto', 'mktx']:
        try:
            to_address = args[1]
            amount = int( 100000000 * Decimal(args[2]) )
            label = ' '.join(args[3:])
            if options.tx_fee: options.tx_fee = int( 100000000 * Decimal(options.tx_fee) )
        except:
            firstarg = cmd
            cmd = 'help'

    # open session
    if cmd not in ['password', 'mktx', 'history', 'label', 'contacts', 'help', 'validateaddress']:
        wallet.new_session()
        wallet.update()
        wallet.save()

    # commands needing password
    if cmd in ['payto', 'password', 'mktx', 'seed' ] or ( cmd=='addresses' and options.show_keys):
        password = getpass.getpass('Password:') if wallet.use_encryption else None

    if cmd=='help':
        cmd2 = firstarg
        if cmd2 not in known_commands:
            print "known commands:", ', '.join(known_commands)
            print "help <command> shows the help on a specific command"
        elif cmd2 == 'balance':
            print "display the balance of your wallet"
        elif cmd2 == 'contacts':
            print "show your list of contacts"
        elif cmd2 == 'payto':
            print "payto <recipient> <amount> [label]"
            print "create and broadcast a transaction."
            print "<recipient> can be a bitcoin address or a label"
        elif cmd2== 'sendtx':
            print "sendtx <tx>"
            print "broadcast a transaction to the network. <tx> must be in hexadecimal"
        elif cmd2 == 'password':
            print "change your password"
        elif cmd2 == 'newaddress':
            print "create a new receiving address. password is needed."
        elif cmd2 == 'addresses':
            print "show your list of addresses. options: -a, -k, -b"
        elif cmd2 == 'history':
            print "show the transaction history"
        elif cmd2 == 'label':
            print "assign a label to an item"
        elif cmd2 == 'gui':
            print "start the GUI"
        elif cmd2 == 'mktx':
            print "create a signed transaction. password protected"
            print "syntax: mktx <recipient> <amount> [label]"
        elif cmd2 == 'seed':
            print "show generation seed of your wallet. password protected."

    elif cmd == 'seed':
        import mnemonic
        seed = wallet.pw_decode( wallet.seed, password)
        print seed, '"'+' '.join(mnemonic.mn_encode(seed))+'"'

    elif cmd == 'validateaddress':
        addr = args[1]
        print wallet.is_valid(addr)

    elif cmd == 't2':
        wallet.create_t2_address(password)

    elif cmd == 'balance':
        c, u = wallet.get_balance()
        if u:
            print c*1e-8, u*1e-8
        else:
            print c*1e-8

    elif cmd in [ 'contacts']:
        for addr in wallet.addressbook:
            print addr, "   ", wallet.labels.get(addr)

    elif cmd in [ 'addresses']:
        if options.show_keys: private_keys = ast.literal_eval( wallet.pw_decode( wallet.private_keys, password ) )
        for addr in wallet.addresses:
            if options.show_all or not wallet.is_change(addr):
                label = wallet.labels.get(addr) if not wallet.is_change(addr) else "[change]"
                if label is None: label = ''
                if options.show_balance:
                    h = wallet.history.get(addr)
                    ni = no = 0
                    for item in h:
                        if item['is_in']:  ni += 1
                        else:              no += 1
                    b = "%d %d %f"%(no, ni, wallet.get_addr_balance(addr)[0]*1e-8)
                else: b=''
                pk = private_keys[wallet.addresses.index(addr)] if options.show_keys else ''
                print addr, pk, b, label

    if cmd == 'history':
        lines = wallet.get_tx_history()
        b = 0 
        for line in lines:
            import datetime
            v = 1.*line['value']/1e8
            b += v
            v_str = "%f"%v if v<0 else "+%f"%v
            try:
                time_str = datetime.datetime.fromtimestamp( line['nTime']) 
            except:
                print line['nTime']
                time_str = 'pending'
            label = line.get('label')
            if not label: label = line['tx_hash']
            else: label = label + ' '*(64 - len(label) )

            print time_str, " ", label, " ", v_str, " ", "%f"%b
        print "# balance: ", b

    elif cmd == 'label':
        try:
            tx = args[1]
            label = ' '.join(args[2:])
        except:
            print "syntax:  label <tx_hash> <text>"
            sys.exit(1)
        wallet.labels[tx] = label
        wallet.save()
            
    elif cmd in ['payto', 'mktx']:
        for k, v in wallet.labels.items():
            if v == to_address:
                to_address = k
                print "alias", to_address
                break
        r, h = wallet.mktx( to_address, amount, label, password, fee = options.tx_fee )
        if r and cmd=='payto': 
            r, h = wallet.sendtx( tx )
            print h
        else:
            print h 

    elif cmd == 'sendtx':
        tx = args[1]
        r, h = wallet.sendtx( tx )
        print h

    elif cmd == 'newaddress':
        s, a = wallet.get_new_address()
        print a

    elif cmd == 'password':
        try:
            seed = wallet.pw_decode( wallet.seed, password)
        except:
            print "sorry"
            sys.exit(1)
        new_password = getpass.getpass('New password:')
        if new_password == getpass.getpass('Confirm new password:'):
            wallet.use_encryption = (new_password != '')
            wallet.seed = wallet.pw_encode( seed, new_password)
            wallet.save()
        else:
            print "error: mismatch"